1. Field of the invention:
This invention relates to a die assembly for use in a press machine, particularly in a general type mechanical press machine in which a slide or ram is moved mechanically through a mechanism such as, for example, crank, eccentric, knuckle, toggle, link, cam, etc.
2. Description of the prior art:
Conventional general type mechanical press machines are adapted to shape a product between an upper die mounted on a slide and a lower die fixedly secured to a bolster by the pressurization of the upper die during its downward movement. In such press machines, products cannot be shaped by synchronous movements of the upper and lower dies towards each other. To achieve shaping of a product by synchronous movements of the upper and lower dies towards each other, the use of a special drive press or a press machine of servo control drive system in which a computer is employed is required, thus causing various disadvantages such as increasing in the dimension of the whole system, increasing in the shaping cost of products and increasing in the work cycle time etc.